by Susan Page, USA TODAY

by Susan Page, USA TODAY

WASHINGTON -- In the end, Kathleen Sebelius was able to resign as secretary of Health and Human Services during a high point, when the administration had just announced that 7.5 million Americans had signed up for insurance through the Affordable Care Act exchanges.

But that moment came only after six months of battering and blame over the botched roll-out of the healthcare.gov website. The enduring image of her five-year tenure as head of the huge agency is likely to be as the silver-haired woman sitting alone at a congressional hearing table, peering over reading glasses as she faced what often seemed to be an inquisition.

Even when President Obama held a victory rally of sorts last week in the Rose Garden, announcing that sign-ups had edged over the original goal of seven million, Sebelius was assigned a front-row seat but wasn't called to join in the camera shot or thanked by name in the president's remarks.

Fairly or not, some in the administration hold her responsible for an IT debacle that has dented Obama's legacy, raised questions about his competence and put Democratic candidates in peril in November. A USA TODAY/Pew Research Center Poll released Thursday showed the danger ahead: A majority of Americans now say the Affordable Care Act will be "very important" in their decision who to support in the midterm congressional elections. Those motivated voters disapprove of Obamacare by 2-1.

Sebelius, now 65, had been accustomed to partisan warfare as the two-term governor of Kansas, a Democrat in a Republican state, though nothing like the pitched divide that now prevails in Washington. She was one of the highest profile Democratic women officeholders to endorse Obama over Hillary Rodham Clinton.

Obama named her to his Cabinet after his first choice to head HHS, former senator Tom Daschle, ran into controversy over a tax issue.

To succeed her, the White House says the president will nominate Budget Director Sylvia Mathews Burwell. A veteran of the Clinton administration, known as meticulous and low-key, she has taken pains to build relationships on Capitol Hill, including with Republicans.